phrase = "Don't panic"
plist = list(phrase)
print(plist)
for i in range(4):
    plist.pop()
print(plist)
#删除字符D
plist.pop(0)
print(plist)
plist.pop(2)
print(plist)
plist.extend([plist.pop(),plist.pop()])
print(plist)
plist.insert(2,plist.pop())
print(plist)
plist.insert(4,"o")
new_phrase = ''.join(plist)
print(new_phrase)
